[Haskell-cafe] XMLParse module

Hello all, I am reading XMLParse module http://www.germane-software.com/repositories/public/StatusReport/trunk/hxml-... But, I am not clear about the purpose of this module and the function of two functions: parseInstance = unfoldr (pRun instanceItem) . pcdataMode parseDTD = foldl (\a b->b a) emptyDTD . unfoldr (pRun dtdItem) . markupMode parseDocument text = case pRun prolog (pcdataMode text) of Just (_, rest) -> unfoldr (pRun instanceItem) rest Nothing -> [ErrorEvent "Error parsing prolog"] -- can't happen. If any knows the meaning of those, please let me know. Thanks a lot. Best regards,